These HO229 and HO249 work forms from Davis Instruments are professionally designed to be used with tables in the Nautical Almanac. They simplify calculations and reduce your margin of error. Each pad has 50 work forms and a transparent, waterproof, press-to-seal carrying case. Four completed examples of working with sun, moon, planet, and stars are included with step-by-step instructions. To work sights for stars only, order the HO249 set of work forms from Davis.